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From: Lance Yang <ioworker0@gmail.com>
Date: Fri, 26 Jan 2024 20:52:12 +0800
Message-ID: <CAK1f24n0152CmPghBLQ7225=rwEuP6mMdBybWZz7heTLzemBqw@mail.gmail.com>
Subject: Re: [PATCH v2 1/1] mm/madvise: add MADV_F_COLLAPSE_LIGHT to process_madvise()
To: akpm@linux-foundation.org, Michal Hocko <mhocko@suse.com>, 
	"Zach O'Keefe" <zokeefe@google.com>, Yang Shi <shy828301@gmail.com>, 
	David Hildenbrand <david@redhat.com>
Cc: songmuchun@bytedance.com, peterx@redhat.com, mknyszek@google.com, 
	minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, 
	linux-api@vger.kernel.org
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On Fri, Jan 26, 2024 at 6:15=E2=80=AFPM Lance Yang <ioworker0@gmail.com> wr=
ote:
[...]
> > If the kernel supports a more relaxed (opportunistic)
> > MADV_COLLAPSE, we will modify the THP settings as follows:
> >
> > echo madvise >/sys/kernel/mm/transparent_hugepage/enabled
> > echo madvise >/sys/kernel/mm/transparent_hugepage/defrag
>
> The correct THP settings should be:
> echo always >/sys/kernel/mm/transparent_hugepage/enabled
> echo madvise >/sys/kernel/mm/transparent_hugepage/defrag
>

Apologize for the confusion in my previous email.

The third type of requirements prefers not to use huge pages at all.
The correct THP settings should be:
echo madvise >/sys/kernel/mm/transparent_hugepage/enabled
echo defer+madvise >/sys/kernel/mm/transparent_hugepage/defrag

> >
> > Then, we will use process_madvise(MADV_COLLAPSE, xx_relaxed_flag)
> > to address the requirements of the second type.
[...]